1. Field
Aspects of the present invention relate to a secondary battery and a secondary battery module.
2. Description of the Related Art
Unlike a primary battery which is not designed to be recharged, a secondary battery can be repeatedly charged and discharged. Low capacity secondary batteries that use single battery cells are used as power sources for various portable, small-sized electronic devices such as cellular phones and camcorders. High power secondary batteries that use a plurality of battery cells connected to each other in a battery pack are used as power sources for hybrid vehicles and electric vehicles.
The secondary battery may be classified into various types, including cylindrical and prismatic batteries. The secondary battery is generally configured by placing an electrode assembly having a positive plate, a negative plate, and a separator as an insulator interposed therebetween in a case with an electrolyte. A current collector and terminals electrically connected to the electrode assembly are included.
Clad metal is often used in a negative electrode of the secondary battery to connect a current collector made of copper to a terminal made of aluminum, which may increase the cost of the battery. In order to establish coupling of the negative electrode, clad metals make contact with and are coupled to other metals, resulting in corrosion at the contact and coupling area due to a potential difference between the metals. The corrosion may be expedited by an electrolyte. In this case, electrical conductivity of a current path including the current collector and the terminal may be lowered and a coupling force between the current collector and the terminal may also be lowered.
In addition, a bulk-type connection structure is generally used to connect the current collector and the terminal, which may increase the weight of the secondary battery.